I realise that I could NOT display the DM, but I prefer to keep an eye on download progress while I carry on with other work. When the D/L completes, that cursed DM steals focus and disrupts my workflow, causing much frustration. It is beneficial to keep a watch on D/L progress, but MOST ANNOYING when focus is stolen! Could this be rectified in a future release? The Download completion notification could be readily replaced by a Status-Line "Number of Current Downloads" and thereby maintain notification, without the current intrusion of THAT particular pest - which ALSO steals focus!

There are any number of browser.download... Prefs in about:config.Maybe something in there can turn off the behavior?(Might want to test in a test Profile.)If the display of the "download manager" can be turned off altogether, then maybe an extension could help you, Download Status Bar, or similar?